Taken from MobyGames featured article on Macrocom:
MobyGames: Was ICON a financial success?
Neal White III: No, but it provided enough income to finance the development of 7 Spirits. :-)
Rand E. Bohrer: But the game was a tremendous success in JAPAN, just not a financial success. Some engineer over there broke our copy protecion. Because the game used special modes, it became popular as a "test" to see if their clone graphics boards were truly compatble. So engineers were our "marketing force" in Japan. Apparently they gave copies out all over the place. Imagine our surprise when we went to Comdex and saw about 2/3 the of the Japanese and Taiwanese graphic board manufacturers using ICON as a demo to show how "superior" the color and animation capabilities of their boards were. We asked some floor rep, a Matsushita engineer I think, if he knew anything about the program, "Ohh, Icon Quest, most popular PC game in Japan, everyone copy it!" Then when he found out we made it, he ran around to other booths, bringing all these Japanese engineers and salesmen to meet us. So that was our 15 minutes of fame.
ICON was one of the very few PC games to use a tweaked 40-column text mode to paint "graphics" with a surprising amount of detail, no doubt inspired by the Commodore 64's "character graphics". It was achieved by changing the character cell height from the normal 8 lines down to only two; the result was an effective resolution of "320x200x16" with the obvious color limitations per character cell.
Check out the screenshots for examples of the advantages (and slight drawbacks) of this unique video mode.
Appears to have been written in Pascal ("Pascal MT+").
Interesting messages found in the game executables and overlays:
Game save file is corrupt - please do not try to edit game files. The file has been deleted for your protection; please start over.
This is an illegal copy of ICON. You should be ashamed of yourself!